1. Field of the Invention
This invention relates to a scleral plug for occluding a hole in the eye and for controlled irrigation during vitreo-retinal surgery in order to maintain a closed system during the procedure, and angled forceps for handling the plugs.
2. Description of Related Art
Modern vitreo-retinal surgery allows ophthalmologists to diagnose and treat diseases of and injuries to the posterior segment of the eye. Vitreo-retinal surgery involves the use of small needle instruments to remove, for example, the vitreous humor, hemorrhage, scar tissue, infection or foreign bodies.
A typical three port vitrectomy utilizes an infusion cannula, which maintains a preset tension in the eye, and multiple hand-held instruments for illumination, cutting, grasping, and suction. A carefully constructed environment must be maintained within the eye at all times for these procedures to be successful. The surgeon uses microsurgical techniques to manipulate the delicate tissue within the eye. The instruments are introduced into the vitreous cavity through sclerotomies, or small holes, in the area of the pars plana ciliaris.
Small steel plugs are utilized during vitreo-retinal surgery to occlude the sclerotomy sites when instruments are not inserted through these access holes in the sclera. The plugs of the prior art have a straight shaft and a cap on one end. Inserting these plugs into the access holes allows the surgeon to maintain a closed system, which is important for the prevention of pressure loss, egress of fluid or globe contents, and entrance of bacteria or debris. These access holes, or sclerotomies, are manipulated by repeated passing of instruments and will tend to stretch and enlarge, allowing the plugs to slip out. There is a need for a scleral plug that will remain in place during vitreo-retinal surgery, allowing a surgeon to maintain a closed system.
Proliferative vitreoretinopathy (PVR) is the leading cause of failure of retinal detachment repair. Although the etiology is somewhat controversial, one theory implicates the retinal pigment epithelial (RPE) cells. RPE cells are “workhorse” type cells with fibroblastic, or scar forming, potential. During formation of retinal tears or treatment with cryotherapy, these RPE cells may be released into the vitreous cavity, increasing the chances of PVR. Currently, during a vitrectomy, the surgeon can irrigate these cells from the eye using a flute needle, called a Charles Needle. This type of irrigation requires the surgeon to manually hold instruments in the eye for 30-60 seconds or more. Thus, there is a need for a plug that would allow controlled egress of fluid without requiring the surgeon's strict attention and active manipulation.
Forceps used in the art to manipulate scleral plugs are currently reverse acting—they grip until you squeeze to release. Thus, the instrument will hold a plug until placed and released by the surgeon. Current forceps have a long, angled tip. The length of the tip, combined with the size of the tiny plug, makes it difficult to place a plug in a sclerotomy. Thus, there is a need for forceps that allow easier placement and more exacting control over placement of plugs.